Year	Percent
1991	65.249
1992	66.74
1993	67.129
1994	63.607
1995	61.571
1996	64.396
1997	65.621
1998	64.275
1999	67.048
2000	67.388
2001	67.891
2002	68.718
2003	68.11
2004	68.589
2005	68.105
2006	68.554
2007	68.631
2008	68.377
2009	68.826
2010	68.943
2011	69.147
2012	68.427
2013	67.955
2014	67.581
2015	67.335
2016	67.452
2017	67.413
2018	67.261
2019	67.022
2020	66.785
2021	66.564
2022	66.331